Jörn Engel - logfs.org

Hard disks are dead. Now what?

Nearly every week some company anounces a Solid State Disk (SSD), a
diskless notebook or some other piece of hardware in which flash has
replaced hard disks as the storage medium. While hard disks certainly
aren't dead yet, a lot of companies seem to bet their money on other
technology. If those companies are right, hard disks will die.

But what happens when hard disks are dead? Manufacturers like to
pretend that SSDs are just like disks, only better. That is
understandable, as it furthers their goal to sell hardware to an
established market. But in fact, flash behaves fundamentally different
to hard disks.

Many attemps exist to make flash behave similar to hard disks, by means
of a so-called Flash Translation Layer or FTL. All these attempts are,
as one might guess, incomplete. Given enough paint, a horse may look
like a zebra from a distance, but it is still a horse.

This presentation will explain the differences between hard disks and
flash. It will further explain a well-documented FTL, smartmedia, in
detail and roughly point out how alternative approaches could work and
the various advantages and drawbacks.